What services exist to improve old photos?

Question

Photo

Recently, more and more old photographs and films have appeared, which have noticeably improved quality in all basic parameters (sharpness, contrast, etc.). Some films and photographs are in color. Obviously, more sophisticated technologies were used than filtering and simple upsizeing using interpolation formulas.
I read somewhere that this is done with ML.
I would be grateful for information (especially experience of using) similar services, including commercial ones.

Answer 1

This is called restoration.
An artist is required.